In the past various types of plastic polyolefin piping has been widely used in a wide range of industrial applications. Such polyolefin pipe, such as polyethylene, polypropylene, polybutylene, polyvinyldenefluoride and the like, has conventionally been coupled together to join pieces of said pipe at their ends by a clamp type coupling having a pair of internal circumferential ribs. One of said ribs engages a circumferential external groove in one of the butted pipe ends while the other rib engages a like groove in the end of the other butted pipe end to form a seal.
While such coupled pipe ends have largely been used in industry for transport of various fluids under pressure a problem has existed from time to time in leakage of the fluid at the coupling. Such leakage in the field has caused a considerable problem in damage caused by leaking fluids and the time and labor involved in maintainance and repair.
Another type of conventional prior art connection of butted ends has been by fusion welding of the butted ends. This necessitates special electrically and gasoline powered fusion welding machines. In the field this is expensive, time consuming, cumbersome and quite often impractical.